A previously proposed openable and closable member control apparatus, such as a lifting apparatus of a window glass of a door of a vehicle (e.g., an automobile), is constructed to move upward or downward the window glass by simply applying a drive voltage to an electric motor that generates a drive force to drive the window glass. Therefore, as shown in FIGS. 7A and 7B, at the time of driving the window glass 101 of the door 100 to its full closing position, the window glass 101 is driven until the window glass 101 urges a glass run channel 102 with an upper end (a tip end) of the window glass 101 and is mechanically locked by a stopper 104 of a window frame 103. Thus, at that time, an excessive collision force may be applied to the window glass 101, the window frame 103 and a drive system (not shown), and thereby, for example, a load applied to the drive system may be disadvantageously increased. Also, an annoying collision sound may be disadvantageously generated.
In order to address the above-described disadvantages, according to a prior art technique, supply of the electric power (supply of the electric voltage) is turned off to rotate the electric motor by inertial rotation and thereby to guide the openable and closable member to the full closing position or the full opening position thereof (see JP2003-3743A).
The technique of JP2003-3743A enables the openable and closable member to be reliably stopped at a target position without being influenced by a change in the operational state of the electric motor and without locking the electric motor.
However, the electric motor is rotated by the inertial force to drive the window glass to the full closing position by stopping the supply of the electric power to the electric motor immediately before reaching of the window glass to the full closing position. This operation is based on the assumption of that the window glass can be driven to the full closing position by the inertial rotation of the electric motor. Thereby, there is a disadvantage of that it is unknown whether the openable and closable member is actually moved to the full closing position.
Furthermore, in general, the openable and closable member, such as the window glass of the window, a roof panel of a sunroof or a slide door, may be driven in the closing direction and mechanically closed while being tilted due to, for example, looseness of a drive force transmission mechanism in a drive path. In such a case, the openable and closable member is driven while a plane of the openable and closable member is slightly tilted (turned) relative to the moving direction of the openable and closable member.
For example, in the exemplary case where the window glass of the window of the vehicle serves as the openable and closable member, as shown in FIGS. 8A to 8D, when the window glass 101, which is tilted due to the looseness, reaches a full closing state thereof, one (a part indicated with A-A line in FIG. 8A) of a left end part and a right end part of the window glass 101, which are respectively located on a left side or a right side in a turning direction (tilting direction) of the window glass 101 in FIG. 8A, first contacts a window glass side end part of a glass run channel 102, which is located at the window and serves as a mating member placed in the moving direction of the window glass 101 (see FIG. 8B).
When the window glass (the openable and closable member) 101 stops in the state where the one of the left end part and the right end part of the window glass 101 first contacts the end part of the mating member placed in the moving direction, a small gap 105 is generated between the window glass 101 and the glass run channel 102 in a state where the window glass 101 is not completely closed at the other one (a part indicated with B-B line in FIG. 8A) of the left end part and the right end part of the window glass 101, as shown in FIG. 8C. Thus, the sealing between the window glass 101 and the glass run channel 102 is deteriorated, and thereby, for example, water may enter a passenger compartment of the vehicle at the time of, for example, washing the vehicle, or a wind noise may be generated at the time of running the vehicle.
Furthermore, for example, as shown in FIG. 8B, the window glass 101 is sealed by the glass run channel 102 placed at the upper side portion of the window frame 103. The glass run channel 102 has a bottom portion 102a, two side portions 102c, an inner seal lip portion 102d1 and an outer seal lip portion 102d2. The side portions 102c extend from the bottom portion 102a while a groove (space) 102b is interposed between the side portions 102c. The inner seal lip portion 102d1 is bent and is urged inwardly from one of the side portions 102c into the groove (space) 102b. 
The outer seal lip portion 102d2 is bent and is urged inwardly from the other one of the side portions 102c into the groove (space) 102b. The window glass 101 is held between the inner seal lip portion 102d1 and the outer seal lip portion 102d2 from the vehicle left side and the vehicle right side (widthwise direction of the vehicle). In the state where the window glass 101 contacts the glass run channel 102 (the mating member), when the window glass 101 is further driven upward toward the upper end side (closing side), a lower portion of the window glass 101 is moved outward (a right outer side pointed with an arrow in FIG. 8D) in the widthwise direction of the vehicle by a component drive force of the window glass 101. Thus, a gap between an inner seal lip portion 106a of a belt molding 106 and the window glass 101 is increased, and thereby a sealing force of the inner seal lip portion 106a is reduced. Also, an outer seal lip portion 106b of the belt molding 106 is urged by the window glass 101 and is thereby deformed. As a result, as shown in FIG. 8D, a positional relationship between the belt molding 106 and the window glass 101 is deviated from a normal positional relationship (a pre-designed position of the window glass 101 relative to the belt molding 106). Thereby, a portion of the belt molding 106, which is placed at the lower side of the window frame 103, is deformed due to the deformation of the outer seal lip portion 106b. As a result, a gap is generated between the belt molding 106 and the window glass 101 to cause generation of the wind noise at the time of running the vehicle.
Therefore, it is desirable that both of the left end part and the right end part (the upper end part and the lower end part) of the openable and closable member can tightly contact the mating member to avoid application of an excess load to the drive system. Also, it is desirable that the seal member (e.g., the glass run channel or the belt molding), which seals the openable and closable member, is not influenced by the openable and closable member.
The mating member (e.g., the glass run channel), which contacts the window glass (the openable and closable member) to place the window glass into the full closing state, is made of a resilient material (e.g., rubber material). Therefore, in the case where the electric motor is controlled to stop when one of the left end part and the right end part of the window glass first contacts the mating member (e.g., the glass run channel), as shown in FIG. 8C, the gap may possibly be generated between the window glass and the mating member due to the influence of the orientation of the window glass at the time of upwardly moving the window glass. Furthermore, in the case where the window glass is stopped in the state where the glass run channel only contacts the upper end part of the window glass, the water may possibly enter the passenger compartment of the vehicle through a gap between the glass run channel and the upper end part of the window glass at the time of washing the vehicle with a high pressure washing machine.
Furthermore, in the case of the window of the door, at the time of placing the window glass (the openable and closable member) into the full closing state, the window glass may possibly deform the belt molding, which is placed at the lower frame portion of the window frame 103, to possibly cause generation of the wind noise at the time of running the vehicle. That is, when the openable and closable member is placed into the fully closing state to fully close the open space of the window, the openable and closable member may possibly cause the deformation of the member, which seals the base side of the open space. This deformation may possibly cause an unstable flow of the wind at the time of running the vehicle to cause generation of the wind noise.
In order to address the above disadvantages, another technique has been proposed (see, for example, JP2014-156767A that corresponds to US2014/0196252A1). According to this technique, a rotational speed (a rotation period) of an electric motor is computed. When the amount of change in the rotational speed of the electric motor exceeds a threshold value, the supply of the electric power to the electric motor is stopped.
The technique of JP2014-156767A (corresponding to US2014/0196252A1) can prevent occurrence of erroneous stop of the openable and closable member in the middle of the opening. Also, according to this technique, a load, which is generated in a state where an opposing portion of the openable and closable member and an opposing portion of the resilient member are entirely urged against each other, is sensed. The supply of the electric power to the electric motor is controlled based on the sensed load, so that the electric motor can be stopped in the state where the opposing portion of the openable and closable member and the opposing portion of the resilient member are entirely urged against each other. Thereby, the required sealing performance of the openable and closable member can be ensured.
However, in a state where the voltage of the electric motor is low, when the above-described control technique is applied to compute the rotational speed (the rotation period) of the electric motor and to stop the supply of the electric power to the electric motor at the time when the amount of change in the rotational speed of the electric motor exceeds the threshold value, the window glass may possibly be stopped without fully closing the opening of the window with the window glass. Therefore, depending on a value of the voltage of the electric motor, the required sealing performance may not be achieved with the window glass.
Thus, there is a demand for a technique that can fully close the window glass even in the low voltage condition where the closing force (drive force) of the electric motor, which drives the window glass to fully close the window glass, is low, thereby limiting deterioration of the sealing performance of the window glass.